Triple-band metamaterial absorber based on electric excitation of split ring resonator magnetic resonance

Abstract

In this paper, an absorber with two nested split ring resonators (SRRs) is introduced that its absorption spectrum has three absorption peaks by the values of 99.8%, 97.52%, and 94.98% at the frequencies of 8.5, 14.7 and 23.9 THz, respectively. In order to understand the performance of the absorber, the proposed structure is excited in two different situations. The simulation results reveal that when the incident electric field is in the direction of the symmetry axis of the structure, an integer number of the whole-wavelength of the current density wave is formed on the SRR and when the electric field is launched in the opposite direction that the structure is asymmetric, the excited modes are an odd number of half-wavelength of the current density wave. The first and third absorption peaks are related to the first and second modes of the SRR and the second absorption peak is due to the resonance of electric filed between the top rod elements. Also, the effect of adding extra arms to the SRRs on the absorption spectrum is investigated.